Alcohol: what ethanol does in the glass

Table wine typically sits between about 11% and 15% alcohol by volume, and fortified wine considerably higher. That range covers a large perceptual distance.

Alcohol is the component most often noticed only when it is out of balance. A well-integrated 14.5% wine does not read as strong; a poorly balanced 13% one can.

WineHQ discusses alcohol as a component of flavour and structure. It makes no health claims, and questions about consumption belong with national health guidance.

Ethanol is less dense than water but more viscous in solution, and it contributes to the sense of weight and texture usually called body. It is not the only contributor — glycerol, residual sugar and dissolved solids all play a part.

It also functions as a solvent. Volatile aroma compounds partition between the liquid and the headspace above it, and ethanol concentration changes that partitioning, which is why the same wine smells different at different strengths and different temperatures.

Perceptually, ethanol has a slightly sweet taste of its own and it suppresses bitterness to some extent, which is part of why higher-alcohol reds can seem rounder.

The burning or warming sensation at higher concentrations is trigeminal — the same tactile-chemical pathway that carries chilli heat — rather than a taste.

Alcohol also raises perceived astringency in some studies and lowers it in others depending on the matrix, which is one of the reasons balance is judged holistically rather than component by component.

Serving temperature interacts with it directly: warmth increases the volatility of ethanol, which is why an over-warm red smells spirity and a chilled one does not.

It also sets a practical limit on food pairing, because high alcohol amplifies the heat of chilli rather than relieving it.